If you export a self contained quicktime from FCP in the RGB colorspace, interpret the color as RGB when you import into Avid. If you export as 601, interpret as 601 when you import into Avid. Then you shouldn’t see a color shift at all.
HOWEVER: If time is an issue, you don’t want to go this route. The time it takes to export a quicktime then import that quicktime into Avid, which Avid will have to transcode to OMF or MXF, will be a killer.
Even if you export your FCP quicktime in an Avid codec, which will speed up your import time into Avid, it will still take forever (depending on the length of your timeline). Even with this “fast” import, though, I think it would be faster just to lay to tape and digitize.
Michael.